Phonograph-horn



E. C. COOK.

PHONOGRAPH HORN.

APPLICAHON FILED JAN.29,1919.

Patented Feb. 3, 1920.

INVENTOR. 5171656 001 BY Q9 ATTORN ERNEST C. COOK, OF CHICAGO, ILLINOIS.

PHONOGRAPH-HORN.

Specification of Letters Patent.

Patented Feb. 3, 1920.

Application filed January 29, 1919. Serial No. 273,726.

To all whom it may conqern:

Be it known that I, ERNEST C. COOK, a citizen of the United States, residing at Chicago, in the county of Cookand State of Illinois, have invented a certain new and useful Improvement in Phonograph-Horns, of which the following is a full, clear, concise, and exact description, referencebeing had to the accompanying drawings, forming a part of this specification.

This invention relates to improvements in phonograph horns.

In the construction of phonographs of the so-called cabinet type, it is customary to employ a horn concealed within the cabinet, which horn is made of wood and flares from its inner or inlet end toward its outer or outlet end. Such horns are generally so constructed that a vertical cross section thereof at any point therealong is substantially rectangular, the bottom wall being flat and extending horizontally, the side walls extending vertically and v the upper wall being curved in such manner as to present a convex surface on the interior of the horn. In phonographs of the type mentioned, the sound waves are delivered from the tone arm of the machine through a connecting memher having a vertical passageway for the sound waves, said passageway terminating at its bottom in an exit opening delivering the sound waves horizontally into the horn. This sound wave conducting passage is made circular so as to present the least amount of interference to the passage of the sound waves.

In the horns of the type above indicated, as heretofore made, the interiors thereof have been of rectangular cross section from end to end with the result that numerous eddying currents are set up in the sound waves as the latter emerge from the circular passageway of the intermediate connecting member between the tone arm and the horn, into the horn having a different interior cross section. Furthermore, due to the interior sharp corners of the flaring horn, additional eddy currents are set up in the sound waves as the latter travel from the inner end of the horn to the outer end thereof in constantly expanding volume. The result of the two sets of eddy currents set up in the sound waves above mentioned, of course, seriously interferes with the quality of the tone'sproduced by the phonograph.

Another difiiculty heretofore experienced in the construction of phonograph horns of the type above indicated resides in the fact that the walls of the horn tend to separate at the corners due to warping of the wood and wide variations of temperature to which the phonographs are ordinarily subjected in houses and apartments where the temperature of'the room variesgreatly. This separation of thewalls at points along the joints permits of. what is known as leaka e of the sound waves which produces a diminishedvolume in-the toneand also interferes with'the proper emission of the sound waves. l

The object. of'my. invention is to provide a phonograph horn, of the type usually employed in so-called cabinet phonographs, which horn will eliminate and overcome the defects and disadvantages of prior horns,

above indicated.

Another object ofthe invention is to provide a phonograph horn of the type indicated which may be'readily manufactured at relatively small expense upon a commercial scale.

The invention furthermore consists in the ir'nprovementsin the parts and devices and in the'novel'combinations of the parts herein show-n, described and claimed.

In the drawing forming a part of this specification, Figure 1 is a central, vertical, sectional view of a phonograph horn embodyingrny improvements. Fig. 2 is a horizontal, sectional view of the horn illustrated in Fig. 1 and taken substantially onthe line 2-2 thereof. Fig. 3 is an elevational view of the improved horn, the view being taken from the outer or large end of the horn looking toward the interior inner end thereof. Fig. 4: is a vertical, sectional view taken substantially on the line 14 of Fig. 1.

. And Fig. 5 is a detail, horizontal, sectional view taken substantially on the line 5-5 of Fig. 1.

In said drawing, the horn proper is desig nated generally by the reference A and the intermediate connecting member between the tone arm and the horn is indicated generally by the reference B. As will be understood, the sound waves are delivered from the tone arm to the top of the member B into the circular passageway as indicated at 10, said passageway 10 extending vertically throughout the greater length of the 110 member B and asshown in Fig. 1 At its lower end, the passageway 1 s ll m n:

taining its circular form throughout, is turned into a horizontal direction as indicated at 11 where the sound waves are delivered to the inner or inlet end of the horn A.

. The connecting member B, as shown, is preferably built up of four blocks of wood indicated at 12, 13, 14 and 15, the same being suitably glued together and cut out to form the passagewa 10. The two blocks 13 and 14 have the ottom of the member B formed therein, the division line between the two blocks 13 and 14 on the one hand and the other blocks 12 and 15 on the other 1 hand being indicated by the line 16 in Fig.

1. To re ulate the intensity of the sound, said mem er B is provided with a transversely slidable plate 17 having a plurality of openings 18 therein of different size, the late 17 havi an enlarged end 19 providing shoulders 0 and a peg 21 to limit the back and forth movements of the slide, as will be understood. By adjusting the slide so as to presentthe proper sized openin 18, it is evident that the intensity or vo ume of the tone may be regulated.

The horn A, as shown, comprises a curved top wall 22, a flat horizontal bottom wall 23,

and vertically extending side walls 24-24.

As shown in Fig. 2, the side walls 24 diverge from the inner end of the horn toward the outer'end and as shown in Fig. 1, there is a gradually increased divergence between the Hat bottom wall 23 and the upwardly curved top wall 22 from the inner end of the horn toward the outer end. The horn is so made that a vertical section thereof taken at any oint therealon 'at right angles to the section shown at ig. 1, gives an exterior outline to the horn which is substantially rectangular as indicated by Figs. 3 and 4. The interior'forination of the'horn, however, is of var ing cross sectional form as hereinafter exp ained.

At each intersection of a pair of any two walls, I provide a molding such as indicated at 25, 26, 27 and 28, as most clearly shown in Figs. 3 and 4. As will. be noted from the drawing, particularly Figs. 3 and 4, each molding has two outer faces extending lengthwise thereof which are arranged at right angles to each other. The two lower corner moldings 25 and 26 are straight throughout their length whereas the two upper corner moldings 27 and 28 are curved in conformity with the curvature of the upper wall 22 of the horn. Each pair of moldings on a side, 25 and 28 on one side and 26 and 27 on the other side, have their opposed vertical edges rabbeted as indicated at 2929, and the corresponding side walls or partitions 24 are seated within the rabbets and firmly glued therein. With this construction, I am enabled to form the sides of the horn in units and to which the upper and lower walls of the horn may be thereafter readily secured by glue and suitable fastening means such as the screws 30-30 shown in Fig. 4. As will be understood, the upper and lower walls 22 and 23 Wlll be made of a plurality of strips of wood because of their comparatively great extent, whereas the side walls 2-'124 are preferably made of single pieces of wood.

Each molding strip 25, 26, 2'7 and 28 is provided with a concaved surface as indicated at 31 extending throughout the length of the molding, the radius of the ooncaved surface 31 closely approximating the radius of the circular passage which delivers the sound Waves from the member '13 into the horn A. As shown in Figs. 1, 3 and 4, the upper moldings 27 and 28 are merged with the lower moldings 26*and 25 as said sets of moldings approach the extreme inner end of the horn. This is preferably done by cutting away on a taper the upper moldings 27 and 28 as indicated at 32 in Figs. 1 and 3.

The concaved surfaces 31 of the corner moldings are so brought together and merged toward the inner or inlet end of the horn that the moldings form a circular interior section at the inner end of the horn immediately adjacent the delivery end 11 of the passage 10 and of an area substantially identical with the area of said delivery end 11. In this manner, it is evident that I minimize the possibility of eddy currents being set up in the sound waves as the latter are delivered from the circular passageway of the member B into the horn, which has heretofore proved such a disadvantage. Furthermore, by forming the interior corners of the horn concave or rounded as described and shown particularly in Figs. 8 and 4, other eddy currents are minimized as the sound waves travel outwardly to the exit end ofthe horn A, the interior cross section of-the horn from its' extreme inner end gradually changing from one which is circular to one which is of generally rectangular form but with rounded corners as shown in Fig. 3, the change being so graduated as to eliminate any sharp corners or projections on the interior of the horn. With this construction, the tone is greatly improved over that produced heretofore by the ordinary construction of horns, as will be appreciated by those skilled in the art.

In rabbeting the moldings and side walls, as hereinbefore described, I eliminate possibility of sound wave leakage since it is practically impossible for any gap or opening to be formed from warping or otherwise between the side wall partitions 24 and the corner moldings. gaps occurring between the top and bottom walls of the horn in the corner moldings is remote due to the fact that said top and bot- The danger of any 7 tom walls in addition to being glued may be and are preferably screwed down at short intervals.

Although I have herein shown and described what I now consider the preferred manner of carrying out the invention, the same is merely illustrative and I contemplate all changes and modifications that come within the scope of the claims appended hereto.

I claim:

1. Aplionograph horn having four'sides tapering from exit to receiving end and comprising corner pieces which on their inner faces are of parti-circular contour, the inner ends of said corner pieces being merged together to form the circumference of a circular entrance opening, said corner pieces being united by side pieces and by top and bottom pieces.

2. A non-metallic phonograph horn having four sides tapering from exit to receiving end and comprising corner pieces which on their inner faces are of parti-circular contour, the inner ends of said corner pieces being merged together to form the circumference of a circular entrance opening, said corner pieces being united by side pieces and by top and bottom pieces.

3. A non-metallic phonograph horn having four sides tapering from exit to receiving end and comprising corner pieces which on their inner faces are of parti-circular contour, the inner ends of said corner pieces being merged together to form the circumference of a circular entrance opening, said corner pieces being united by flat vertical side pieces and by top and bottom pieces which are straight in a transverse direction.

4. A non-metallic phonograph horn having four sides tapering from exit to receiving end and comprising corner pieces which on their inner faces are of concave contour,

and on their outer faces are of angular contour, the inner ends of said corner pieces being merged together to form the circumference of the entrance opening, said corner pieces being united byfiat vertical side ieces and by top and bottom pieces whic are straight in a transverse direction.

In Witness that I claim the foregoing I have hereunto subscribed my name this 21st day ofJan. 1919.

ERNEST C. COOK.

IVitnesses MARTIN MADsoN, G. H. CRANDALL, Jr. 

